The present invention relates to window shades, and more particularly to such shades having bamboo slats, the slats themselves, and methods for making the slats.
Slats of conventional Venetian blinds are typically made of thin metal or plastic strips, the use of either of these types of material presents significant environmental risks, in the form of pollution, depletion of non-renewable resources, damage to surface features, and various combinations thereof. Wood has also been used for making the slats of blinds, but this material is increasingly scarce and expensive, particularly when selected and processed for uniformity, dimensional stability, and appearance.
As a result of these and other considerations, bamboo has also been used to fabricate slats. The use of bamboo for the slats of blinds provides significant advantages in preservation of the environment, in addition to the potential of improved appearance. However, there are significant problems to be overcome, such as susceptibility to impact damage and weathering, and dimensional instability. See, for example, U.S. Pat. Nos. 5,896,903 and 6,192,949 to the present inventor, and U.S. Pat. No. 6,098,680 Chen, each of these patents being incorporated herein by this reference.
Although some of the above difficulties are addressed in the patents referenced above, the bamboo slats as used in Venetian blinds of the prior art are still not entirely satisfactory in that they exhibit dimensional instability and weathering due to the effects of exposure to the sun and moisture, and in at least some cases they are not economical to produce.
Thus there is a need for slats of bamboo and blinds made therefrom, as well as a method for producing such slats, that overcomes the disadvantages of the prior art.
The present invention meets this need by providing blinds slats that are particularly resistant to warping and other forms of deterioration when subjected to repeated exposure to the sun and moisture, the slats being formed as composites having a major proportion of bamboo and a minor proportion of wood. In one aspect of the invention, a composite blinds slat includes a bonded plurality of bamboo strips forming a center portion of the slat; and a pair of wooden strips bonded to opposite edges of the center portion, the wooden strips being flush with opposite sides of the center portion. Each of the bamboo strips and/or each of the wooden strips can form portions of opposite major faces of the blinds slat. The major faces can be planar and parallel. As used herein, the terms xe2x80x9cwoodxe2x80x9d and xe2x80x9cwoodenxe2x80x9d are exclusive of bamboo.
The composite blinds slat can also include a further pair of bamboo strips bonded opposite the pair of wooden strips to form respective edge portions of the blinds slat. The edge portions can be shaped to form respective rounded edge margins of the blinds slat. Also, or alternatively, each of the edge portions can include a pair of bamboo strips.
The wooden strips can include or be formed of basswood. Also, a plurality of clearance passages can be formed between opposite major faces of the blinds slat for locating the slat in a blinds assembly. Further, the invention provides a blinds assembly including a plurality of the blinds slats having the clearance openings.
In another aspect of the invention, a method for forming a composite blinds slat includes providing a plurality of bamboo strips having adhesive coatings thereon; providing a plurality of wooden strips; bonding a pair of the wooden strips together with the bamboo strips such that a majority of the bamboo strips extend in parallel adjacency between the wooden strips; and smoothing opposite surface extremities of the bamboo and wooden strips to form flush and continuous major faces of the composite blinds slat. The method can further include forming a plurality of clearance passages between the major faces of the slat. The bonding can further include bonding an additional pair of the bamboo strips opposite the pair of wooden strips to form respective edge portions of the blinds slat.
The providing can of respective pluralities of bamboo and wooden blanks, the bonding can be of the respective bamboo and wooden blanks to form a block having a majority of the bamboo blanks extending in parallel adjacence between a pair of the wooden blanks to form a block, the method further including parting the block to form a plurality of composite blanks, and the smoothing can be of opposite side of the blanks to form respective major faces of a plurality of blinds slats. Further, the bonding can be of a larger number of the respective bamboo and wooden blanks to form a composite plank, with the parting further including separating the plank into a plurality of composite blocks, thereby to form a multiplicity of the blinds slats.